Set core frequency in main
Set core frequency in main

* Set core frequency using rcc_ctrl

iabdalkader/openmv,tianzhihen/openmv,SmartArduino/openmv,kwagyeman/openmv,SmartArduino/openmv,SmartArduino/openmv,iabdalkader/openmv,kwagyeman/openmv,SmartArduino/openmv,tianzhihen/openmv,tianzhihen/openmv,iabdalkader/openmv,openmv/openmv,tianzhihen/openmv,openmv/openmv,kwagyeman/openmv,iabdalkader/openmv,kwagyeman/openmv,openmv/openmv,openmv/openmv